KHOLINA A.B., ARTYUKOVA E.V., SANDANOV D.V., POZDNYAKOVA T.E.
Izvesniya Saint-Petersburg state agrarian university 2026; (3(85)): 62-75
Section Xerobia Bunge, one of the ancient sections of the genus Oxytropis DC. (Fabaceae), is composed of rare, relict, endemic, medicinal and economically valuable species, many of which are vulnerable and protected. In Southern Siberia, where the northern boundary of the section's range is located, populations of valuable species are isolated and sparse, requiring an assessment of their genetic resources for conservation and use. For this purpose, the genetic diversity and demographic dynamics of 27 populations of 10 species of Oxytropis species of section Xerobia were studied using the analysis of nucleotide polymorphism of cpDNA intergenic spacers psbA-trnH, trnL-trnF, and trnS-trnG. All populations, except one monomorphic, were characterized by medium or high levels of haplotype diversity, with the majority of them (77,8%) having a high level (h from 0,667 to 1,000); one-third of the populations had medium or high levels of nucleotide diversity (n from 0,0030 to 0,0122). 76,5% of the populations were in a state of demographic equilibrium. Nine highly polymorphic populations of seven species, including the medicinal species O. grandiflora and O. leptophylla, which were in a state of long-term population stability and located within presumed ancient microrefugia, are particularly valuable as a reserve of genetic variability. Complicated intra-sectional relationships have been identified, including the presence of a complex of congeneric species O. grandiflora, O. nitens, O. caespitosa, O. leucotricha, and O. mixotriche, the chloroplast genomes of which are poorly differentiated. Thus, the northern boundary of the Xerobia section's range is a center of speciation and high genetic diversity, and therefore specific measures are needed to conserve these populations.
